Malicious PDF — malware analysis report

Static analysis result for SHA-256 fdc1441d5a4cce38…

MALICIOUS

PDF

9.6 KB
MD5: 26fdcb9d27b87845773996606cec712e SHA-1: 6c71cdf9ec8075bb6c96ba7a68b5f2642373cbe5 SHA-256: fdc1441d5a4cce384a52f4fc5b88b8aed3784d33b0fe76ae7ead99fa85fc5702
268 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.001 Malicious Link

The PDF document contains embedded JavaScript that utilizes the 'eval' and 'unescape' functions, indicating obfuscation. Critical heuristics identify the use of 'Collab.collectEmailInfo' and a hex stager, strongly suggesting exploitation of CVE-2007-5659. This technique is commonly used to download and execute further malicious content. The ClamAV detection further corroborates the malicious nature of the file.

Heuristics 9

  • Collab.collectEmailInfo — CVE-2007-5659 critical CVE exact CVE_2007_5659
    PDF JavaScript calls Collab.collectEmailInfo — CVE-2007-5659 is a buffer overflow in Adobe Reader triggered by a long argument or heap-sprayed message field passed to Collab.collectEmailInfo(). Part of a series of Acrobat JS API exploits. (identified after JavaScript deobfuscation)
  • ClamAV: Pdf.Exploit.Agent-35912 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-35912
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
  • Annotation subject callee-key hex JavaScript stager high PDF_ANNOT_SUBJECT_CALLEE_HEX_STAGER
    PDF JavaScript uses syncAnnotScan()/getAnnots() to read an indirect annotation /Subject stream, percent-decodes it through marker replacement, then uses a callee.toString()-derived key to decode and eval the final exploit stage.
  • JavaScript action low PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • syncAnnotScan annotation-staging primitive low PDF_FOXIT_SYNCANNOTSCAN
    PDF JavaScript calls syncAnnotScan() — a no-op annotation-enumeration primitive used by exploit-kit JavaScript to stage payload reads from annotation /Subject fields before eval(). Not a vulnerable sink itself; rarely seen in legitimate PDFs. (matched in decompressed stream)
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0007_000.js
7218a1c68060953321573daa035b16f5f32928ce25a9eb656690dbe78cd9464e
pdf-javascript-stream PDF /JS object 7 at offset 0x19B 201 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
annotation_subject_callee_hex_stage_000.js
25552d3a283c3c28fe405d357ca0898274380c58993756158fc1d49d3da3ba45
deobfuscated-js annotation-subject callee-key decoded JavaScript at offset 0x14A 5236 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s).
legacy_pdfkit_stage_001.js
f3b3a1536029c7711ef28be96e5b7409f4a9b0ff1ab893ff8c6cc17ae91ab9bb
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x2B5 12339 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
deobfuscated.js
33366602fd93609d2d06f4eb6796a3812bcd7aff6e122036d47637e49708fe08
deobfuscated-js PDF JavaScript deobfuscation pass 47689 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).